Emerging applications, such as radio frequency identification (RFID) integrated circuits, high density memory devices have an increasing demand for thin semiconductor devices. Thin semiconductor devices, and the like, enable more sophisticated manufacturing technologies, including micro-electro-mechanical systems (MEMS), through-silicon via (TSV) and novel 3D packaging technologies.
In the manufacturing process of thin semiconductor devices, an important step is thin wafer cleaning after the semiconductor manufacturing process. For example, after a chemical-mechanical polishing process, some residues such as carbon or adhesive films and particles may stay on the surface of the thin wafer. These films and particles may cause surface roughness leading to defects in subsequent fabrication processes, such as a defect in the photolithography process due to the uneven surface of the wafer.
In the conventional art, wet wafer cleaning is commonly employed to remove unwanted residues by spraying various cleaning chemical solvents on a wafer. When a wafer is in this wafer cleaning process, it may be directly placed on a vacuum chuck and then a variety of spray nozzles spray chemical solvents first onto the wafer while the vacuum chuck is spinning. After carbon and adhesive films and particles are dissolved or decomposed, the chemical solvents wash dislodged films and particles away from the wafer. In the last step of the cleaning process, de-ionized water is sprayed while the wafer is spinning to allow complete cleaning.
However, thin wafers are fragile and must be supported over their full dimensions to prevent unnecessary damage. A common method of protecting a thin wafer involves using an adhesive layer to temporarily bond the thin wafer on a plate and employing a wafer frame to prevent the thin wafer from moving laterally. As such, it is desirable to clean a thin wafer while the thin wafer is bonded on a tape layer and protected by a wafer frame.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale.